1. Field of the Invention
The invention relates to a displacement detector of a platform for an exercise apparatus, and more particularly, to a device utilizing a rope, a rotating element and a detecting means mounted either on one side of the platform or on a connection piece for exactly controlling the loading displacement of the platform. Therefore, the detected value serves as reliable reference in measuring and adjusting the supporting force of the cushioning unit.
2. Description of the Related Art
To take a treadmill as example for the above-mentioned exercise apparatus. In general, the treadmill is provided with cushioning units at suitable places for achieving a proper cushioning effect. Meanwhile, the supporting force of the cushioning unit plays an important part in enhancing the comfort of the operator during a workout session. Moreover, a complete and direct protection from injuries of both feet of an operator is dependent upon the functioning of the cushioning unit. At present, hydraulic or pneumatic cylinders are often used to provide a more excellent cushioning effect. A few prior arts such as U.S. Pat. No. 4,591,147, U.S. Pat. No. 5,184,988, U.S. Pat. No. 4,974,831, U.S. Pat. No. 4,984,810, U.S. Pat. No. 5,072,928, U.S. Pat. No. 5,372,559, etc. have disclosed hydraulic or pneumatic cylinders applied to the treadmill for meeting different using needs.
As everyone knows, the exercise on the treadmill can be classified into warm-up walking, jogging with constant speed, speed-up jogging and slow-down walking to restore the heart beat to an optimal state. Therefore, the force acting on the treadmill's platform is not a constant value; for example, the walking and jogging exercises make much difference in the applied force. Accordingly, the optimal cushioning force can't be reached in certain stages during the whole workout session if the cushioning force is set at a predetermined value. For example, the operator feels comfortable under the influence of the cushioning unit set at a predetermined value during a slow walking session. However, he will feel during a jogging session that the supporting force under same influence of the cushioning unit is insufficient and his feet sink too much. This is an important factor that causes exercise injuries. Of course, the operator can adjust the cushioning unit to raise cushioning force immediately when he feels that it's too little. However, the operator has to interrupt his workout session. Moreover, he will still be unsatisfied with cushioning force when he changes the speed-up jogging session to the slow-down walking session again. Thus, this brings him much trouble and disappointment about the treadmill.
In addition, an operator with heavier weight would feel that the cushioning force is too slight while an operator with lighter weight could feel that it is too strong if the cushioning force is fixed at a certain value. Besides, different operators have their own subjective feeling about the cushioning strength no matter how large or slight the cushioning force is. In addition, some operators have special rehabilitation requirements thereto. Accordingly, the prior arts are required for improvement.